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diff --git a/spec/ruby/core/array/shuffle_spec.rb b/spec/ruby/core/array/shuffle_spec.rb
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+++ b/spec/ruby/core/array/shuffle_spec.rb
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+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "Array#shuffle" do
+  it "returns the same values, in a usually different order" do
+    a = [1, 2, 3, 4]
+    different = false
+    10.times do
+      s = a.shuffle
+      s.sort.should == a
+      different ||= (a != s)
+    end
+    different.should be_true # Will fail once in a blue moon (4!^10)
+  end
+
+  it "is not destructive" do
+    a = [1, 2, 3]
+    10.times do
+      a.shuffle
+      a.should == [1, 2, 3]
+    end
+  end
+
+  it "does not return subclass instances with Array subclass" do
+    ArraySpecs::MyArray[1, 2, 3].shuffle.should be_an_instance_of(Array)
+  end
+
+  it "attempts coercion via #to_hash" do
+    obj = mock('hash')
+    obj.should_receive(:to_hash).once.and_return({})
+    [2, 3].shuffle(obj)
+  end
+
+  it "calls #rand on the Object passed by the :random key in the arguments Hash" do
+    obj = mock("array_shuffle_random")
+    obj.should_receive(:rand).at_least(1).times.and_return(0.5)
+
+    result = [1, 2].shuffle(random: obj)
+    result.size.should == 2
+    result.should include(1, 2)
+  end
+
+  it "raises a NoMethodError if an object passed for the RNG does not define #rand" do
+    obj = BasicObject.new
+
+    lambda { [1, 2].shuffle(random: obj) }.should raise_error(NoMethodError)
+  end
+
+  it "accepts a Float for the value returned by #rand" do
+    random = mock("array_shuffle_random")
+    random.should_receive(:rand).at_least(1).times.and_return(0.3)
+
+    [1, 2].shuffle(random: random).should be_an_instance_of(Array)
+  end
+
+  it "calls #to_int on the Object returned by #rand" do
+    value = mock("array_shuffle_random_value")
+    value.should_receive(:to_int).at_least(1).times.and_return(0)
+    random = mock("array_shuffle_random")
+    random.should_receive(:rand).at_least(1).times.and_return(value)
+
+    [1, 2].shuffle(random: random).should be_an_instance_of(Array)
+  end
+
+  it "raises a RangeError if the value is less than zero" do
+    value = mock("array_shuffle_random_value")
+    value.should_receive(:to_int).and_return(-1)
+    random = mock("array_shuffle_random")
+    random.should_receive(:rand).and_return(value)
+
+    lambda { [1, 2].shuffle(random: random) }.should raise_error(RangeError)
+  end
+
+  it "raises a RangeError if the value is equal to one" do
+    value = mock("array_shuffle_random_value")
+    value.should_receive(:to_int).at_least(1).times.and_return(1)
+    random = mock("array_shuffle_random")
+    random.should_receive(:rand).at_least(1).times.and_return(value)
+
+    lambda { [1, 2].shuffle(random: random) }.should raise_error(RangeError)
+  end
+end
+
+describe "Array#shuffle!" do
+  it "returns the same values, in a usually different order" do
+    a = [1, 2, 3, 4]
+    original = a
+    different = false
+    10.times do
+      a = a.shuffle!
+      a.sort.should == [1, 2, 3, 4]
+      different ||= (a != [1, 2, 3, 4])
+    end
+    different.should be_true # Will fail once in a blue moon (4!^10)
+    a.should equal(original)
+  end
+
+  it "raises a RuntimeError on a frozen array" do
+    lambda { ArraySpecs.frozen_array.shuffle! }.should raise_error(RuntimeError)
+    lambda { ArraySpecs.empty_frozen_array.shuffle! }.should raise_error(RuntimeError)
+  end
+end